The present invention is directed to an automatic engine shut down device and to systems incorporating such device.
More particularly, the present invention is directed to such a device for use in a system of the type including a pump and an engine operating the pump, whereby the shutdown device operates, at the occurrence of the removal or substantial reduction of suction at the inlet of the pump to automatically shut down the engine, thereby preventing damage to the pump.
More specifically, the present invention is directed to a compact, portable water purification system for producing potaable drinking water from contaminated or turbid water, such system employing the automatic engine shut down device.
There are known various purification systems for purifying contaminated or turbid water to produce potable drinking water. Such known systems include various filters and purifying devices, a pump to pump contaminated water through the filters and purifying devices, and an engine for operating the pump.
However, such known systems suffer from the inherent disadvantage that should the suction at the inlet of the pump be substantially reduced or removed, continued operation of the pump will cause severe damage to the pump. Thus, it is, of course, a known fact that an engine transmits energy to the device which it drives, in this case a pump. In the event that the pump flow stops due to loss of suction at the inlet of the pump, with the engine continuing to run, the energy transferred from the engine to the pump will convert to heat and eventually cause severe damage to the pump.
Systems are known for automatically shutting down the engine when electrical power is available, such systems employing flow switches or pressure switches operating control valves.
U.S. Pat. No. 2,634,681 discloses a system for reducing engine speed upon loss of fluid being pumped by a pump. U.S. Pat. No. 3,567,338 discloses a system whereby reduction of pump pressure causes an engine spark plug to be shorted out, thereby stopping the engine. U.S. Pat. Nos. 3,756,747 and 3,806,279 disclose governor systems for compressors wherein an increase in compressor pressure decreases engine speed. U.S. Pat. No. 3,864,059 discloses a closed hydraulic system whereby engine speed and torque output are regulated to meet load demand.
All such known systems, however, fail to solve the problem of automatically shutting down an engine, upon the removal or substantial reduction of suction at the inlet of a pump, by physically removing a supply of fuel or engine driving fluid to the engine.